JP2013541763A - Creating a physical disk to virtual disk by obtaining data from important sectors (P2V) - Google Patents

Abstract

  Virtual disks can be created by using data from critical sectors on the main physical disk. Virtual disk creation involves receiving sector numbers and corresponding data for critical sectors on the main physical disk on the main computing system, creating virtual disks containing sectors, and virtual sectors from the key sectors on the main physical disk. With writing data to each sector of the disk.

Description

  The present invention relates to disk creation, and more particularly to creating a virtual disk from a physical disk.

  Conventional methods for creating virtual disks from physical disks include the use of virtualization programs. These virtualization programs can create a virtual disk from a physical disk, and can copy data to the virtual disk for each sector.

  Generally, data is organized and backed up for each file different from each sector. Accordingly, a problem may occur when copying backup data to a virtual disk for each file.

  Various systems and methods for creating a virtual disk from a physical disk by obtaining data from critical sectors are disclosed.

  For example, the method receives a sector number of a critical sector of a first physical disk on a primary computing system, receives corresponding data from a critical sector of the first physical disk, and creates a virtual disk A step in which the virtual disk includes sectors and a step of writing data from the critical sectors of the first physical disk to the sectors of the virtual disk, each sector being identified by a sector number. Step.

  In some embodiments, the method can also be performed on a second physical disk on the primary computing system. The method includes receiving a second sector number of a second critical sector of a second physical disk on the primary computing system and second corresponding data from the second critical sector of the second physical disk. And a step of creating a second virtual disk, wherein the second virtual disk includes sectors, and from the second important sector of the second physical disk, Writing data to each sector, each sector being identified by a second sector number.

  In certain embodiments, the method may also involve accessing the virtual machine upon a failure in the primary computing system or the first physical disk, the virtual machine accessing the virtual disk.

  In some embodiments, the sector number and corresponding data from the critical sectors of the first physical disk are received during a backup operation.

  In some embodiments, the method includes the step of backing up user data in a file stored on the first physical disk, wherein the user data is backed up as a file and stored on a backup server. Can accompany. In some embodiments, user data is received from a backup server and written to a virtual disk.

  In some embodiments, the method may also include mounting the volume on a virtual disk and formatting the volume according to a file system.

  An example system may include one or more processors and memory coupled to the one or more processors. The memory stores program instructions that can be executed to perform the method as described above. Similarly, such program instructions can be stored on a computer-readable storage medium.

  The above is a summary and thus necessarily includes simplifications, generalizations and omissions of details, so that those skilled in the art will appreciate that this summary is only an example and is in no way limiting. You will understand that is not intended. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the following non-limiting modes for carrying out the invention.

  The invention can be better understood and its numerous objects, features, and advantages will become apparent to those skilled in the art by reference to the accompanying drawings.

FIG. 2 is a block diagram illustrating relevant components of a system for providing business continuity according to one embodiment of the invention. 6 is a flowchart illustrating related aspects of an example method for creating a virtual disk in accordance with one or more embodiments of the present invention. FIG. 6 is a block diagram illustrating relevant components of a backup server for creating a virtual disk, in accordance with one or more embodiments of the present invention. FIG. 3 is a block diagram illustrating the relevant components of an example physical disk and a corresponding created virtual disk according to one or more embodiments of the invention. 6 is a flowchart illustrating related aspects of an example method for providing business continuity according to one or more embodiments of the invention. 1 is a block diagram of a computing system. 1 is a block diagram of a networked system.

  While the invention is susceptible to various modifications and alternative forms, specific embodiments of the invention are shown by way of example in the drawings and the detailed description. It should be understood that the drawings and detailed description are not intended to limit the invention to the particular forms disclosed. The present invention is intended to embrace all such alterations, equivalents and alternatives that fall within the spirit and scope of the invention as defined by the appended claims.

  Business continuity is a property that allows a business to resume processing transactions with minimal downtime after a major computing system fails. A primary computing system typically includes a computer system (eg, a server), an operating system, at least one application, data, and memory that are used together to process a business transaction. Business continuity is possible by using virtual machines that run on one or more secondary servers. When the primary computing system fails, the virtual machine is called to act as a substitute for processing transactions as quickly and seamlessly as possible.

  FIG. 1 is a block diagram illustrating relevant components of a system for providing business continuity. As shown, the system includes a main computing system 100. Although not shown, additional primary computing systems may be included. The primary computing system 100 is typically used by businesses to process business transactions received from other computer systems (eg, clients). The main computing system 100 includes a server 102 that communicates with a disk array 104. Communication between the server 102 and the disk array 104 may occur via the SAN 106. The disk array 104 includes a main physical disk 108. Further, although not shown, the disk array 104 may include additional physical disks. In certain embodiments, physical disks may be formed as a logical collection of physical memory from one or more disks in disk array 104.

  At a predetermined time, backup of data on the main physical disk 108 is performed by the backup server 110. The backup data 112 is then stored in the memory 114 by the backup server 110.

  The system of FIG. 1 also includes a secondary computing system 120. The secondary computing system 120 includes a server 122 that implements a virtual machine 124 that functions as a failover to the primary computing system 100. Although not shown, the server 122 may implement another virtual machine that functions as a failover to another major computing system, also not shown. The virtual machine 124 is used when the main computing system 100 fails. If the primary computing system 100 fails, the business transaction can be redirected to the virtual machine 124.

  In the event of a failure, the business wants the failover to be as quick and uninterrupted as possible. Before the virtual machine performs redirected commerce processing, the corresponding virtual disk is ideally set up to have the same organization as the primary physical disk.

  In general, a primary computing system is composed of one or more primary physical disks. For ease of explanation, the primary computing system 100 is described as having one physical disk 108. The primary physical disk stores one or more volumes, which in turn can store the file system.

  Before the virtual machine starts the redirected transaction process, a corresponding virtual disk is created for each main physical disk. A virtual disk can be formed from one or more underlying secondary physical disks. The secondary computing system 120 is illustrated as having a secondary disk array 126 that communicates with the server 122 via the SAN 128. Secondary disk array 126 includes secondary physical disks 130 on which virtual disks 132 can be created. Two or more virtual disks may be created using the secondary physical disk 130. In certain embodiments, virtual disks may be formed as a logical collection of physical memory from one or more disks in secondary disk array 126.

  A common method of creating a virtual disk involves the use of a virtualization program and a corresponding application program interface (API). With this API, it becomes possible to create an empty virtual disk, followed by storage of backup data in the virtual disk for each sector.

  The problem with this approach is that many businesses prefer to back up data on a file basis rather than on a sector basis. Sector information is more basic information than file information. Furthermore, the file information may not be continuous, and therefore simple mapping between file information and sector information is not possible. Therefore, available virtualization program APIs require the use of a backup system that operates on a sector-by-sector basis rather than on a file-by-file basis.

  Therefore, it is desirable to have a method of creating a virtual disk so that backup data for each file can be stored in the virtual disk using an available virtualization program. By doing this, if the virtual disk is already configured to receive data in such a format, the backup data organized by file is transferred to the corresponding files and folders in the virtual disk. It can be written quickly.

  FIG. 2 illustrates the relevant aspects of an example method for creating a virtual disk. The method shown in FIG. 2 makes it possible to create a virtual disk, and to copy backup data for each file to the virtual disk using an API of a well-known virtualization program.

  The method begins at 210 with a receiving module (eg, backup server) on the computer system receiving a sector number and corresponding data for the main sector from the main physical disk. Critical sectors can be identified during the backup process that takes place on the primary computing system. Critical sectors may include sectors in the primary physical disk that have information used to operate the primary physical disk and to identify the geometry of the primary physical disk. The disk geometry includes elements such as boot code, disk signature, partition layout on a physical disk, and volume information in the case of a dynamic disk.

  Examples of critical sectors may include a master boot record (MBR), an extended partition boot record (EBR), a logical disk manager (LDM), and an extensible firmware interface (EFI) sector. The MBR is generally the first sector of the physical disk. EPBR is used to handle logical volumes within the main physical disk. LDM is used to handle dynamic disks. The EFI sector is used to handle the GUID partition table.

  Once critical sectors are identified, sector numbers and data corresponding to each critical sector are collected and stored in storage accessible by the backup server. An example of critical data collected for a primary physical disk includes four critical sectors: (1) MBR with sector number 0 and data D1, (2) EBR1 with sector number 4954450 and data D2, (3) EBR2 with sector number 193390470 and data D3, and (4) EBR3 with sector number 21443390656 and data D4.

  The method proceeds to 220 where the backup server creates an empty virtual disk 220. This empty virtual disk can be created by using the virtualization program API and a secondary physical disk array that communicates with the backup server. Examples of virtualization programs include VMware and Hyper-V. An example of an empty virtual disk created by one of these virtualization programs is virtual_disk. vmdk or virtual_disk. It may be a file having an extension such as vhd.

  As shown at 230, the critical data is then written to an empty virtual disk. The important data is written in each sector position of the virtual disk using the sector number received in 210.

  At 240, the backup server determines that the number of primary physical disks on the primary computing system (ie, indicated by the primary disk array including several hard disks) is the number of virtual disks created for the virtual machine (ie, To determine if it is equal to the secondary disk array containing several hard disks). The primary disk array in the primary computing system may include multiple primary physical disks. For each primary physical disk present in the primary computing system, a corresponding virtual disk is desired to store the geometry of the primary computing system.

  If there are two or more primary physical disks in one primary computing system, the backup server creates a second virtual disk, as indicated at 250. As shown at 230, the important data for the second main physical disk is written to the second virtual disk at each sector position.

  This approach (ie, represented by 240 with decisions leading to 250 and 230) is such that each primary physical disk on the primary computing system has a corresponding virtual disk in the secondary disk array, and thus the primary physical disk Iterate until the backup server determines that the number of disks is equal to the number of virtual disks.

  By writing important data to each virtual disk, an appropriate volume is created in each virtual disk. As indicated at 260, the volumes in each virtual disk are then mounted. At this point, the volume is in an unformatted state.

  At 270, the volumes in each virtual disk are formatted. Each volume in the virtual disk is formatted according to the file system. Examples of file systems include a file allocation table (FAT), a 32-bit file allocation table (FAT32), or a new technology file system (NTFS).

  At 280, user data is read from the backup. User data is periodically collected and backed up at a predetermined time. For example, a business can choose to back up user data daily at a particular time of day. This backup data is typically stored in memory accessible by the backup server, but can also be stored in memory accessible by the primary computing system.

  As shown at 290, the user data is then written to each virtual disk at each file and folder location. Once user data is written to each virtual disk, the process ends. The method of FIG. 2 may be repeated during each backup of the primary computing system to create a new virtual disk or update an existing virtual disk.

  When the method of FIG. 2 is complete, the virtual disk is ready to be accessed by the virtual machine in the event of a major computing system failure. Thus, the operation of FIG. 2 allows virtual machines (ie, central processing unit and memory) to operate in a warm standby mode, thereby saving computing resources.

  In the event of a failure, the virtual machine can begin operation, have immediate access to the virtual disk, and can begin processing redirected transactions. When accessed by the virtual machine, the virtual disk contains the latest user data up to the point of the last backup made on the primary computing system. At this point, additional user data (created after the last backup) may be added to update the user data to the latest version that existed just before the failure occurred.

  FIG. 3 shows the relevant components of a backup server for creating a virtual disk. As shown, backup server 310 includes a plurality of modules that may take the form of software instructions executing on one or more processors.

  First, as shown at 320, the backup server 310 may include a receiving module for receiving important data. This important data includes a sector number and corresponding data regarding the important sector of each main physical disk. Once received, this important information can be stored in the virtual disk 330 as important data 335.

  The second module is a disk processing module for creating and processing a virtual disk, as indicated by 340. The disk processing module 340 can create empty virtual disks, create appropriate volumes by writing important data to each virtual disk, mount these volumes, and format the volumes according to the file system. . The disk processing module 340 can use the virtualization program and its API to perform these operations.

  The backup server 310 may also include a conversion module such as 350 for reading and writing backup data to and from the virtual disk for each file. The conversion process is performed as part of the backup process and may be repeated for each backup.

  FIG. 4 is a block diagram illustrating the relevant components of the example main physical disk and the corresponding example virtual disk. As shown, the primary physical disk 410 has critical sectors 420, 422, 424, and 426. Further, the main physical disk 410 also includes user data stored in files and folders using a specific file system for each volume.

  Critical sectors 420, 422, 424, and 426 are generally identified during backup of the physical disk 410. A sector number is assigned to each important sector, and the corresponding data in each important sector is saved along with the assigned sector number. This important data is then copied to the corresponding virtual disk after the corresponding virtual disk is created using the secondary physical disk in the secondary disk array.

  The virtual disk 430 ideally has the same critical data as the primary physical disk 410 (ie, the same number of critical sectors and the same data in each critical sector), particularly after the method of FIG. 2 has been implemented by the backup server. Including. As shown, the virtual disk has critical sectors 440, 442, 444, and 446 that coincide with critical sectors 420, 422, 424, and 426 in both content and sector locations.

  Further, after the conversion has occurred, the virtual disk 430 ideally contains user data read from memory and uses the same file system implemented within each volume of the main physical disk, Save the data in files and folders.

  FIG. 5 illustrates related aspects of an example method for providing business continuity. The method begins at 510 where user data on the primary physical disk is backed up.

  At 520, important data is identified and collected from each primary physical disk. The critical sectors of each major physical disk on the major computing system are identified and the corresponding sector numbers and data are collected. This important data is then written to the empty virtual disk after creation of the empty virtual disk. The identification, collection, and writing performed at 520 can occur at the same time as the backup process is performed.

  As shown at 530, the virtual machines in the secondary computing system are maintained in a cold standby mode. In the cold standby mode, user data in each virtual disk is not read during backup (as in the warm standby mode). Instead, user data is written to each virtual disk after a failure occurs in the primary computing system.

  At 540, a determination is made as to whether a failure has occurred in the primary computing system. A failure in the primary computing system can be due to a disk failure and can cause the primary computing system to be partially or completely unusable. When a failure is detected on the primary computing system, the virtual machine begins operation as indicated at 550. The virtual machine can then access the virtual disk created to correspond to the primary physical disk.

  As shown at 560, user data is read from the backup after a failure occurs and after the virtual machine is started. As shown at 570, the user data is then written to each virtual disk at each file and folder location. Once user data is written to each virtual disk, the process ends. Writing user data to each virtual disk can take a significant amount of time to complete. This is why it is preferable to operate the virtual machine in a warm standby mode (eg, as shown in FIG. 2).

  FIG. 6 is a block diagram of a computing system 610 suitable for performing virtual disk creation as described above. The computer system 610 includes a central processing unit 614, a system memory 617 (generally a RAM, but may also include a ROM, a flash RAM, etc., and may also include a disk processing module 340), an input / output control device. 618, external audio device such as speaker system 620 via audio output interface 622, external device such as display screen 624 via display adapter 626, serial ports 628 and 630, keyboard 632 (interfaces with keyboard controller 633) A storage interface 634, a floppy disk drive 637 that functions to receive a floppy disk 638, and a host bus adapter that functions to connect to a fiber channel network 690. The main sub-system of the computer system 610, such as a data bus (HBA) interface card 635A, a host bus adapter (HBA) interface card 635B that functions to connect to the SCSI bus 639, and an optical disk drive 640 that functions to receive the optical disk 642 It includes a bus 612 that interconnects the systems. Also included are mouse 646 (or other point-and-click device coupled to bus 612 via serial port 628), modem 647 (coupled to bus 612 via serial port 630). And network interface 648 (coupled directly to bus 612).

  By bus 612, data between central processing unit 614 and system memory 617, which may include read only memory (ROM) or flash memory (both not shown) and random access memory (RAM) (not shown) as described above. Communication is possible. The RAM is generally main memory into which an operating system and application programs are loaded. ROM or flash memory may include a basic input / output system (BIOS) that controls basic hardware operations, such as interaction with peripheral components, among other codes. Applications resident in computer system 610 are typically computer readable media such as hard disk drives (eg, fixed disk 644), optical drives (eg, optical drive 640), floppy disk device 637, or other storage media. Stored and accessed through it. Further, the application may be in the form of an electronic signal that is modulated according to the application and data communication technology when accessed via the network modem 647 or interface 648.

  Similar to other storage interfaces of computer system 610, storage interface 634 may be connected to standard computer readable media for storage and / or retrieval of information, such as fixed disk drive 644. Fixed disk drive 644 may be part of computer system 610 or may be separate and accessed via other interface systems. Modem 647 may provide a direct connection to a remote server via a telephone link or to the Internet via an Internet service provider (ISP). The network interface 648 may provide a direct connection to a remote server via a direct network link to the Internet via a point of presence (POP). The network interface 648 may provide such connections using wireless technologies including digital cellular telephone connections, Cellular Digital Packet Data (CDPD) connections, digital satellite data connections, and the like.

  Many other devices or subsystems (not shown) may be connected as well (eg, document scanners, digital cameras, etc.). Conversely, not all of the devices shown in FIG. 6 need be present to implement the present invention. These devices and subsystems can be interconnected in different ways than shown in FIG. The operation of a computer system is readily known in the art and will not be described in detail in this application. Code for implementing the invention may be stored on a computer readable storage medium, such as one or more of the system memory 617, fixed disk 644, optical disk 642, or floppy disk 638. The operating system provided in the computer system 1010 is MS-DOS (registered trademark), MS-WINDOWS (registered trademark), OS / 2 (registered trademark), UNIX (registered trademark), Linux (registered trademark), or any other known system. May be an operating system.

  Further, with respect to the signals described herein, one of ordinary skill in the art can transmit signals directly from the first block to the second block, or change signals between blocks (eg, amplification, It will be appreciated that it can be attenuated, delayed, latched, buffered, inverted, filtered, or otherwise modified. While the signals of the above embodiments are characterized as being transmitted from one block to the next, in other embodiments of the invention signal information and / or functional aspects are transmitted between blocks. As long as it is done, a modified signal may be included instead of such a directly transmitted signal. To some extent, the signal input in the second block is derived from the first signal output from the first block due to physical constraints of the circuits involved (eg, there will always be some attenuation and delay). It can be conceptualized as two signals. Accordingly, in this specification, the second signal obtained from the first signal is due to circuit constraints or other circuit elements that do not change the information and / or final functional aspects of the first signal. It includes the first signal or any modification of the first signal, whether by passing.

  FIG. 7 is a block diagram of a network architecture 700 in which client systems 710, 720, and 730 and servers 740 and 745 can be coupled to a network 750. Client systems 710, 720, and 730 generally represent any type or form of computing device or system, such as computing system 610 of FIG.

  Similarly, servers 740 and 745 generally represent computing devices or systems, such as application servers or database servers, that are configured to provide various database services and / or execute specific software applications. Represent. Network 750 generally represents any communication or computer network including, for example, an intranet, a wide area network (WAN), a local area network (LAN), a personal area network (PAN), or the Internet. In one example, client systems 710, 720, and / or 730, and / or servers 740 and / or 745 may include a disk processing module 340 as shown in FIGS.

  As shown in FIG. 7, one or more storage devices 760 (1)-(N) may be directly connected to the server 740. Similarly, one or more storage devices 770 (1)-(N) may be directly connected to server 745. Storage devices 760 (1)-(N) and storage devices 770 (1)-(N) are generally any type or form of storage device or medium capable of storing data and / or other computer-readable instructions. Represents. In certain embodiments, storage devices 760 (1)-(N) and storage devices 770 (1)-(N) may be network file systems (NFS), server message blocks (SMB), or common Internet file systems (CIFS). ) May represent a network attached storage (NAS) device configured to communicate with the servers 740 and 745 using various protocols.

  Servers 740 and 745 may also be connected to a storage area network (SAN) fabric 780. The SAN fabric 780 generally represents any type or form of computer network or architecture capable of facilitating communication between multiple storage devices. SAN fabric 780 may facilitate communication between servers 740 and 745 and multiple storage devices 790 (1)-(N) and / or intelligent storage array 795. SAN fabric 780 also allows devices 790 (1)-(N) and array 795 to appear as locally attached devices to client systems 710, 720, and 730 via network 750 and servers 740 and 745. In addition, communication between client systems 710, 720, and 730 and storage devices 790 (1)-(N) and / or intelligent storage array 795 may be facilitated. Similar to storage devices 760 (1)-(N) and storage devices 770 (1)-(N), storage devices 790 (1)-(N) and intelligent storage array 795 generally have data and / or Represents any type or form of storage device or medium capable of storing other computer readable instructions.

  In certain embodiments, referring to the computing system 610 of FIG. 6, a communication interface may be used to provide connectivity between each of the client systems 710, 720, and 730 and the network 750. Client systems 710, 720, and 730 may be able to access server 740 or 745 information using, for example, a web browser or other client software. With such software, the client systems 710, 720, and 730 are transferred to the server 740, the server 745, the storage devices 760 (1) to (N), the storage devices 770 (1) to (N), and the storage device 790 (1). ~ (N), or data hosted by intelligent storage array 795 may be accessible. Although FIG. 7 depicts the use of a network (such as the Internet) to exchange data, the embodiments described and / or illustrated herein are limited to the Internet or any particular network-based environment It will never be done.

  In at least one embodiment, all or part of one or more of the embodiments disclosed herein are encoded as a computer program and are server 740, server 745, storage device 760 (1)-( N), storage devices 770 (1)-(N), storage devices 790 (1)-(N), intelligent storage array 795, or any combination thereof may be loaded and executed thereby. All or part of one or more of the embodiments disclosed herein are encoded as a computer program, stored on a server 740, executed by the server 745, and client systems 710, 720 on the network 750. , And 730 may be distributed.

  In some examples, all or some of the computing devices of FIGS. 1, 3, 4, 6, and 7 may represent part of a cloud computing or network-based environment. A cloud computing environment may provide various services and applications over the Internet. These cloud-based services (eg, software as a service, platform as a service, infrastructure as a service, etc.) are accessible via a web browser or other remote interface obtain. Various functions described herein may be provided via a remote desktop environment or other cloud-based computing environment.

  Further, one or more of the components described herein can convert data, a physical device, and / or a representation of a physical device from one form to another. For example, the disk processing module 340 in FIG. 3 can convert the received important data into a virtual disk.

  Although the present invention has been described in connection with some embodiments, it is not intended that the invention be limited to the specific form set forth herein. On the contrary, the intention is to cover such alternatives, modifications and equivalents as may be reasonably included within the scope of the invention as defined by the appended claims.

Claims (20)

Receiving the sector number of the critical sector of the first physical disk on the primary computer system;
Receiving corresponding data from the critical sector of the first physical disk;
Creating a virtual disk,
The virtual disk includes sectors; and
Writing data from the critical sectors of the first physical disk to the respective sectors of the virtual disk;
Each of the sectors is identified by the sector number; and
Including methods. Receiving a second sector number of a second critical sector of a second physical disk on the primary computing system;
Receiving second corresponding data from the second critical sector of the second physical disk;
Creating a second virtual disk, comprising:
The second virtual disk includes sectors; and
Writing data from the second critical sector of the second physical disk to each sector of the second virtual disk;
The respective sectors are identified by the second sector number; and
The method of claim 1, further comprising: Accessing a virtual machine in the event of a failure in the primary computing system or the first physical disk, comprising:
The method of claim 1, further comprising the virtual machine accessing the virtual disk.   The method of claim 1, wherein the critical sector comprises one of a master boot record sector, an extended boot partition sector, a logical disk manager sector, and an extensible firmware interface. Mounting a volume on the virtual disk;
Formatting the volume according to a file system;
The method of claim 1, further comprising:   The method of claim 1, wherein the sector number and corresponding data from the critical sector of the first physical disk are received during a backup operation. Backing up user data in a file stored on the first physical disk, comprising:
The user data is backed up as a file;
Storing the user data in a backup server;
The method of claim 1, further comprising: Receiving the user data from the backup server;
Writing the user data to the virtual disk;
The method of claim 7, further comprising: Receiving the sector number of the critical sector of the first physical disk on the primary computing system;
Receiving corresponding data from the critical sector of the first physical disk;
Creating a virtual disk,
The virtual disk includes sectors;
Writing data from the critical sector of the first physical disk to each sector of the virtual disk;
Each sector is identified by the sector number;
A computer-readable storage medium containing program instructions capable of executing The program instructions are
Receiving a second sector number of a second critical sector of a second physical disk on the primary computing system;
Receiving second corresponding data from the second critical sector of the second physical disk;
Creating a second virtual disk,
The second virtual disk includes sectors;
Writing data from the second critical sector of the second physical disk to each sector of the second virtual disk,
Each of the sectors is identified by the second sector number;
The computer-readable storage medium of claim 9, further executable. The program instructions are:
Accessing a virtual machine in the event of a failure in the primary computing system or the first physical disk,
The computer-readable storage medium of claim 9, wherein the virtual machine is further capable of accessing the virtual disk. The program instructions are:
Mounting a volume on the virtual disk;
Formatting the volume according to a file system;
The computer-readable storage medium of claim 9, capable of executing:   The computer-readable storage medium of claim 9, wherein the sector number and corresponding data from the critical sector of the first physical disk is received during a backup operation. The instructions are
Backing up user data in a file stored on the first physical disk,
The user data is backed up as a file;
Storing the user data on a backup server;
The computer-readable storage medium of claim 9, further executable. The program instructions are:
Receiving the user data from the backup server;
Writing the user data to the virtual disk;
The computer-readable storage medium of claim 14, further executable. A virtual machine,
One or more processors;
A memory coupled to the one or more processors,
Receiving the sector number of the critical sector of the first physical disk on the primary computing system;
Receiving corresponding data from the critical sector of the first physical disk;
Creating a virtual disk,
The virtual disk includes sectors;
Writing data from the critical sector of the first physical disk to each sector of the virtual disk;
Each sector is identified by the sector number;
A memory for storing program instructions executable by the one or more processors;
Including the system. The program instructions are
Receiving a second sector number of a second critical sector of a second physical disk on the primary computing system;
Receiving second corresponding data from the second critical sector of the second physical disk;
Creating a second virtual disk,
The second virtual disk includes sectors;
Writing data from the second critical sector of the second physical disk to each sector of the second virtual disk,
Each of the sectors is identified by the second sector number;
The system of claim 16, further operable. The program instructions are:
Accessing a virtual machine in the event of a failure in the primary computing system or the first physical disk,
The system of claim 16, wherein the virtual machine is further capable of accessing the virtual disk. The program instructions are:
Mounting a volume on the virtual disk;
Formatting the volume according to a file system;
The system of claim 16, further executable.   The system of claim 16, wherein the sector number and corresponding data from the critical sector of the first physical disk is received during a backup operation.